Here’s your bypass:

In OOBE, go through MS account creation. Tell it you were born today. It’ll let you set a password for the MS account before rejecting you due to COPA requirements. At this point, you can make an offline account without having even created an MS account, let alone having to use one.

This will not go away - it’s a legal thing. MS doesn’t want to deal with COPA stuff for very young kids, so this flow exists. Enjoy.